1. Field of the Invention
The present invention relates to a headrest for use with an automotive seat. More particularly, the invention is directed to an inclinable headrest with a headrest stay to be mounted on the seat, which is formed by inserting a part of the headrest stay in the interior of a preformed three-dimensional trim cover assembly, then injecting a liquid foaming material therein, and finally subjecting those trim cover assembly, liquid foaming material and part of the headrest stay to foaming integrally together.
2. Description of Prior Art
There has been known an inclinable headrest for use with an automotive seat, which typically has a pair of headrest stays to be mounted on a top of the seat and can be adjustably tilted forwardly and backwardly relative to the two headrest stays. In most instances, this kind of headrest is formed with a pair of elongated openings in the bottom wall thereof, through which such pair of headrest stays pass, respectively, thereby allowing those particular two headrest stays to move along the two elongated openings relative to a center of rotation in the headrest. As such, the headrest itself is free to be tilted in a fore-and-aft direction without interference with the headrest stays.
In assembling the headrest, a pair of headrest stays or a headrest frame integral with those two stays are first inserted into the interior of a preformed three-dimensional trim cover assembly having a pair of elongated openings formed in the bottom wall thereof, while projecting the two headrest stays outwardly through the respective two elongated openings. Then, a liquid foaming material is injected in the interior of trim cover assembly, followed by a foaming step wherein the trim cover assembly, liquid foaming material and a part of the headrest stays are foamed integrally together, using a foaming die device.
In the foaming step, a leakage of the liquid foaming material through the two openings has been a problem, and therefore, various means and solutions thereto has been used and proposed. In particular, as disclosed in the Japanese Laid-Open Patent Publication No. 6-86608, a tubular plastic material is provided within a headrest trim cover assembly and is sewn at its upper edge with the peripheral edges of an opening defined in the trim cover assembly, through which opening a headrest stay extends outwardly. The tubular plastic material in this prior art surrounds the perimeter of the headrest stay, thereby serving to preclude the headrest stay opening from being loosely opened. But, the tubular plastic material has to be provided independently of the trim cover assembly and requires a hard and troublesome sewing with the edges of headrest stay opening, which results in reducing a rapidity and efficiency in production of headrest. Further, the tubular material is of a relatively hard property that can not be attached closely about the perimeter of the headrest stay, and thus, it is highly possible that a liquid foaming material will be leaked through a small clearance between the tubular material and headrest stay.
As a solution to the problem, the inventor of the present invention previously developed an improved structure of headrest which is disclosed from the U.S. Pat. No. 5,681,088 assigned to the same assignee as in the present invention. According thereto, a headrest trim cover assembly having an elastic property has a pair of integral extensions defined in an opening which is formed in the trim cover assembly to allow a headrest stay to pass therethrough. Such two integral extensions are both folded downwardly from the edges of that opening and sewn together in the interior of trim cover assembly such that an elongated slot area and a through-hole area are defined in the sewn two extension, wherein the through-hole area is substantially equal in diameter to the headrest stay. The elongated slot area allows a fore-and-aft movement of the headrest stay so that a resulting headrest body may be tilted forwardly and backwardly relative to the headrest stay, whereas the through-hole area is closely attached about the headrest stay. Therefore, during a foaming process subjecting the trim cover assembly and headrest stay to foaming together integrally, both two extensions are brought to intimate contact with each other, whereby it is possible to completely prevent leakage of a liquid foaming material through those two holes.
However, the two folded extensions project relatively long within the trim cover assembly. This has been found defective when it is applied to a doughnut-like annular shape of headrest, because such long projected extensions can not be accommodated in the annular inner conduit of such doughnut-like headrest. Also, even in other normal kinds of headrests than the doughnut-like headrest, the long projected extensions has been found defective in that, at a foaming step, a liquid foaming material injected in the trim cover assembly is not sufficiently expanded and cured around those particular long extensions.
In view of the above-stated drawbacks, it is therefore a primary purpose of the present invention to provide an improved headrest which is not only capable of making short two folded extensions which project inwardly of headrest trim cover assembly and allow insertion of a headrest stay therethrough, but also is of a simplified structure for preventing leakage of a liquid foaming material through the two folded extensions during a foaming process.
To achieve such purpose, the headrest in accordance with the present invention basically comprises:
at least one headrest stay;
a trim cover assembly of three-dimensional configuration conforming to an outer shape of the headrest;
the at least one headrest stay being placed in the trim cover assembly, with a part of the headrest stay passing through a predetermined point on the trim cover assembly and projecting outwardly therefrom;
a foam padding provided within said trim cover assembly, said foam padding being formed and filled therein by a foaming process including the step of injecting and curing a liquid foaming material within the trim cover assembly;
the trim cover assembly including:
at least one first extension which is defined at the predetermined point and folded therefrom in a direction inwardly of the trim cover assembly;
at least one second extension which is defined at the predetermined point and folded therefrom in a direction inwardly of the trim cover assembly;
the at least one first extension being greater in length than the at least one second extension, thus having a region extending beyond a free end of the at least one second extension;
wherein such region of the at least one first extension has a through-opening means defied therein, said through-opening means being so arranged as to allow the headrest stay to pass therethrough while being able to be attached closely about a peripheral surface of the headrest stay;
wherein those first and second extensions are contacted and fixedly joined with each other, so that a through-opening area is defined therebetween at the predetermined point, wherein one side of the through-opening area is opened outwardly of the trim cover assembly while another side thereof is opened inwardly of the trim cover assembly;
wherein the afore-said region of the first extension is folded about the free end of the second extension, so that the thus-folded region closes and seals the foregoing another side of the through-opening area, with said through-opening means laying thereover; and
wherein the headrest stay passes through the through-opening area and the through-opening means.
Accordingly, the first extension can be folded by an amount generally half the second extension, so that it is possible to reduce the length of the whole two extensions to a minimum degree by reducing the length of second extension to a smallest possible amount. Hence, both two extensions are made small in projection, which allows both of them to be accommodated in a relatively small space area within a trim cover assembly. Further, such small projection of extensions avoids insufficient foamed points therearound.
Other various features and advantages will become apparent from reading of the descriptions hereinafter, with reference to the annexed drawings.